Noisy Lifters - Sounds Like a Diesel - 1993 3.1

[buickapollo]

Hi all,

I've searched a number a forums with this problem I have with my mother in law's car and haven't been able to find a similar situation to mine. It's a 93 with a 3.1, 175K, was running fine. She drove to our house - everything was running good - She went to start it up to leave and it sounded like the engine kicked back from the starter..but started. The lifters - sounds like all of them - sounded like they had collapsed like there was no oil pressure. It was like there was a powerstroke diesel under the hood! It ran although rough. Oil pressure good, no coolant in the oil. She attempted to drive it home about three miles (against my advice), barely making it before it died...it didn't seize up though. I'm thinking the knock sensor told the ecu to retard the timing so much it wouldn't run. Can a slipped timing chain cause this? That's what has been suggested to me. And from what I've read these 3.1's are interference engines..but I'm wondering how far the cam/crank timing can be off before the valves kiss the pistons. Like I mentioned it still runs..but poorly. Any help would be appreciated! I've already got a motor lined up in case it needs it...but I'd rather just to a chain kit. Also is the oil pressure sender hole located before or after the oil goes through the filter?

Thanks
Colin

[pocket-rocket]

I'm not sure about the timing retard before you get contact, but the OPSU is between the filter and pump. I know this from my days of using junk Fram filters. My gauge on the 91 would peg from the filter being a restriction after the pump causing high pressure between the two. Once I moved to Purolator filters my gauge functioned normally.

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[TGP37]

She went to start it up to leave and it sounded like the engine kicked back from the starter..but started.

I too would suspect a jumped timing chain considering what you wrote there. Or a snapped camshaft, but you said there is oil pressure......Maybe a busted valve?

The knock sensor is only allowed to pull so much timing. I think the engine can still run at max retard (even though it may have zero get-go).


Does it restart after it cooled down?

[buickapollo]

Thanks for the replies. It will start....but not unless the throttle is all the way to the floor...then you have to hold it about mid throttle to keep it running...if I try to decelerate or accelerate once it starts it dies. Did get a backfire out of the throttle body once when attempting to start it. It seems all cylinders are misfiring not just one.

[TGP37]

Backfire in the intake isnt tooo bad, these motors fire the spark plug once per crank revolution. That includes the exhaust stroke. If the combustion spark fails to ignite, fresh air/fuel can ignite in the exhaust stroke. Which the intake valve opens soon after.

Best is to break it down. 4 areas to rule out or investigate.

Compression - Air - Fuel - Spark


I too suspect a timing chain jump, mostly from what you said happened. Should retard the cam enough to explain why it runs with throttle and dies at idle. Retarding pushes efficiency up in rpm range.

You could remove a spark plug and use a simple feeler to determine TDC. Rotate the crank with a socket wrench at the crank pulley until you are at TDC. Then look at the valve springs behind the valve cover. Should have exhaust just closed and intake about to open. Basically the slight over lap of int/exh should be at TDC. If the over lap is any where other then TDC, timing chain jumped.

Keep in mind there will be 2 crank rotations per 1 cam rotation. this is the easiest way to test timing chain that i can think of w/o having to tear into the engine.

[buickapollo]

Well pulled the front valve cover off found 1 busted rocker arm and another one turned with the pushrod floppng around. looking through the intake valley to the other side it looks like a couple pushrods broke also. Any idea what would have caused this?

[TGP37]

Well pulled the front valve cover off found 1 busted rocker arm and another one turned with the pushrod floppng around. looking through the intake valley to the other side it looks like a couple pushrods broke also. Any idea what would have caused this?

Jumped timing chain, the engine will smack valves into the pistons. The weakest link fails first, the rods and rockers. Probably have a bunch of bent valves and cracked pistons too.

Well, you found the problem. Unfortunately it could be a repair beyond the cost of the car, unless you can do it yourself or swap the motor. I'm not saying its a total loss, but it looks bad if your rockers are busted and some pushrods are broken. The pistons probably cracked. I had a piston crack just from a busted valve seat bouncing around for 2 seconds running.

Sorry to say it, sounds bad.

[pocket-rocket]

Not to disagree but I've repaired plenty of engines with bent valves from tong belts going and haven't seen a cracked piston from it yet. Valve seats are harder than valve heads, so I can see it from a seat.

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[buickapollo]

The cam still moves, but I can hear the chain making noise just turning it over with a wrench. Slipped chain. Fortunately I work at a auto recycler and am getting a motor for $300 w/ only 120K and will do the install myself...she will survive! Thanks for your help

[TGP37]

Not to disagree but I've repaired plenty of engines with bent valves from tong belts going and haven't seen a cracked piston from it yet. Valve seats are harder than valve heads, so I can see it from a seat.

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No problem, I rather learn something then remain ignorant. Pieces of the valve seat were embedded into the head, the quench spot was chewed up good.

At least the guy can get a replacement for such a good price, save the car.

[TGP37]

The cam still moves, but I can hear the chain making noise just turning it over with a wrench. Slipped chain. Fortunately I work at a auto recycler and am getting a motor for $300 w/ only 120K and will do the install myself...she will survive! Thanks for your help

Glad to hear you have an inexpensive solution. I bet you had a priceless face expression when you saw the busted rockers/pushrods.